An experimental study on the hydrodynamic performance of the underflow breakwater with two unequal baffles

Abstract

In our previous paper (Li et al., 2022), the hydrodynamic characteristics of the underflow breakwater with two identical baffles were experimentally studied. In this work, the properties of an underflow breakwater with two unequal baffles on the front and back sides is investigated with respect to the hydrodynamic characteristics of this type of breakwater. Different parameters, including the relative blockage of front baffle, breakwater width, relative water depth, and two water surface states between two baffles, is considered under the regular and irregular waves. First, the resonance phenomenon is analyzed under the regular wave conditions. It has been observed that the resonance period is influenced by the width of the breakwater and the minimum relative blockage between the two baffles. The resonance has significant influence on the hydrodynamics of the breakwater characteristics. Thereafter, the transmission coefficient and reflection coefficient are studied. The transfer function of the breakwater under irregular wave is calculated. The transfer functions of different frequency spectrums are nearly identical and coincide with the transmission coefficients under regular waves. The results also indicate that this type of breakwater provides a better protection against short-period waves, whereas its effectiveness in the protecting against long-period waves is relatively weak. The results can be employed as a reference for practical engineering.